Outgoing Octopus: flat, Agile or Prime?

Choosing between Octopus Energy's flat, half-hourly and peak-window Outgoing export tariffs.

Octopus Energy’s three Outgoing tariffs value the same measured export in different ways. One pays a flat rate, one follows the half-hourly wholesale market and one pays more during a fixed early-evening window.

Choosing between them is mainly a question of timing. A solar-only home normally exports when the sun is producing more than the home needs. A home with a battery may be able to hold that surplus and export it later. The best tariff is the one that pays most for the export pattern the system can actually deliver after losses and household demand, not the tariff with the highest advertised rate.

Current prices and terms

The following figures are correct as at 22 July 2026. They should be checked before switching because the flat rate is variable and new fixed-term tariff versions can be introduced.

Tariff	Payment structure	Current contract description
Outgoing Octopus	12p/kWh at any time	Variable rate
Agile Outgoing Octopus	Wholesale-linked half-hourly rates	12-month fixed term, locked formula, no exit fee
Prime Outgoing Octopus	16p/kWh from 4pm to 7pm; 9p/kWh otherwise	12-month fixed term, locked formula, no exit fee

All three need half-hourly export-meter data. They are separate from Octopus’s combined Flux import-and-export tariffs and from its lower export-only SEG offer.

Flat Outgoing

Flat Outgoing is the simplest to model:

annual export payment = metered export in kWh × export rate

Timing does not affect the payment while the flat rate remains unchanged. This can suit a solar-only property whose surplus naturally leaves around the middle of the day, or anyone who does not want to schedule a battery around an export tariff.

The rate is variable. Octopus reduced it from 15p/kWh to 12p/kWh on 1 March 2026 after leaving it unchanged since 2022. That history is useful only as a reminder that “flat” describes the rate within a day, not a guarantee that it will remain fixed indefinitely.

Agile Outgoing

Agile Outgoing assigns a different rate to every half-hour. Octopus uses EPEX day-ahead wholesale data together with regional adjustments in its export formula. The formula is version-specific, so the applicable tariff quote matters more than a coefficient table copied into an article.

The payment over a period is:

sum of each half-hour’s metered export × that half-hour’s export rate

Octopus describes the wholesale-linked rates as uncapped. That means there is no advertised upper limit equivalent to the Agile import cap. Its maintained Outgoing FAQ says that when the underlying calculation falls below zero, the customer is not charged to export and the Outgoing rate stops just above zero.

Agile only outperforms a flat tariff if enough electricity reaches the grid in sufficiently valuable half-hours. A yearly national average cannot answer that question for an individual home. A battery may improve the timing, but it cannot create energy and it loses some electricity while charging and discharging.

Prime Outgoing

Prime uses two known time bands rather than 48 changing rates. At the prices current on 22 July 2026, its weighted average is:

9p + (7p × share of export sent between 4pm and 7pm)

For that weighted rate to exceed the current 12p flat tariff, more than three-sevenths of all export must land in the peak window. That is about 43%.

This is a mathematical break-even point, not a prediction. A property might meet it in summer but not winter, or might sacrifice valuable self-consumption to do so. If the tariff prices change, the threshold changes immediately.

A solar-only home will often export most before 4pm and may struggle to reach the threshold. A sufficiently large battery can shift solar surplus into the window, subject to its state of charge, discharge power and the home’s own evening demand.

Use the home’s data, not a tariff average

The strongest comparison uses half-hourly export data from the property’s smart meter. At least a full year is preferable because solar output and evening demand change markedly by season.

For each candidate tariff:

Apply its rates to each half-hour of actual export.
If modelling a different battery schedule, cap charging and discharging at the real power and usable-capacity limits.
Apply round-trip losses and preserve any backup reserve.
Allow household demand to consume generation or battery discharge before any remainder reaches the export meter.
Check that the proposed export remains within the DNO-agreed export limit.
Compare the result with the import cost and self-consumption value affected by the same schedule.

Repeating last year’s export against this year’s tariff can show sensitivity, but it is not a forecast of either future sunlight or future Agile prices.

The self-consumption test

Exporting 1 kWh has an opportunity cost. If that unit could instead avoid buying 1 kWh later, its self-consumption value is roughly the import price avoided after allowing for storage losses.

For example, a high export rate does not justify emptying a battery if the household then imports more expensive electricity before the next cheap charging opportunity. Conversely, deliberately importing to charge and later export cannot be assessed from the rate spread alone. The calculation also includes:

charging and discharging losses
any standing or transaction costs affected by the tariff choice
VAT and policy costs included in import but not recovered on export
battery wear and warranty throughput
the value of keeping backup reserve

Optimisation software can do the arithmetic repeatedly, but the financial boundary still needs to be defined correctly.

Grid-charged battery export

There is a tension in Octopus’s published material. Its older Outgoing FAQ describes charging a battery from the grid and exporting later. Its general export terms say Octopus is not obliged to pay for “brown export”, including electricity exported from batteries rather than generated by an eligible generation asset.

The contract should be treated as controlling. Obtain written confirmation before building a tariff strategy around grid-to-battery-to-grid trading. The fact that a smart meter records export does not by itself establish that every exported unit is eligible for payment.

Export of solar energy stored in a battery is easier to reconcile with the purpose of the tariff, but mixed energy sources can be difficult to distinguish at a single boundary meter. Keep the system diagram and ask Octopus how it will treat the proposed operating mode.

Operational limits that change the result

A theoretical schedule can overstate earnings if it ignores the installation:

Export limit: the inverter or export controller may cap the combined output from solar and battery.
Battery power: a 5kW battery cannot necessarily export 15kWh in a three-hour window while also supplying the home.
Usable capacity: the nameplate capacity is not all available for each cycle.
Conversion losses: energy passing through the battery returns fewer kWh to the AC system.
State of charge: poor solar weather may leave little surplus to move into Prime’s window.
Warranty: additional cycling can consume a warranted throughput allowance or accelerate wear.
Meter data: missing half-hourly readings can trigger the fallback payment rules in Octopus’s export terms.

These limits are why generic annual earnings claims are misleading. The answer depends on the specific system and its measured flows.

A practical choice

Flat Outgoing is the baseline. It requires no timing decision and makes each exported unit worth the same amount.

Prime is easier to assess than Agile. Calculate the share of export that can genuinely reach the grid between 4pm and 7pm, then compare the resulting weighted rate with flat Outgoing. Re-run the calculation if either rate changes.

Agile offers the greatest exposure to price variation and demands the most detailed modelling. It can reward a battery that can identify and use valuable half-hours, but recent average prices or one exceptional event do not prove that it will beat the alternatives for a particular home.

Before moving, confirm the tariff version, current rates, import-tariff compatibility, permitted battery behaviour and effective switch date in writing.